Atroposelective attack of nucleophiles and electrophiles on 2-acyl-1-naphthamides and their enolates

Abstract

Organolithiums, Grignard reagents and borohydride reducing agents attack 2-acyl-1-naphthamides to give tertiary and secondary alcohols with high or complete atroposelectivity. High levels of stereoselectivity can also be obtained in the alkylations of enolates derived from the same ketones, though the low barrier to thermal epimerisation of the product ketones prevents accurate determination of the kinetic stereoselectivity of the alkylation. The direction of attack in both cases is controlled by the perpendicular conformation of the aromatic amide substituent, whose NR₂ group shields one face of the ketone.